The present invention relates to a cooling system for a wheel type working vehicle having a working implement in the front and an engine in the rear.
FIG. 10 is a side elevation of a wheel type working vehicle. This working vehicle, generally indicated by reference numeral 1, has a vehicle body 2. A working implement 3 used for scooping and loading is mounted in the front of the vehicle body 2. An engine compartment 10 incorporating an engine 4 and a radiator 50 is disposed in the rear of the vehicle body 2. The engine compartment 10 consists of a hood 11, a pair of side covers 12 spaced from each other, and a radiator shutter 13. Each side cover 12 is provided with an intake port 14. The radiator shutter 13 is provided with exhaust ports 15.
FIGS. 11 and 12 are schematic plan views showing examples of the prior art working vehicle. In FIG. 11, a cooling fan 20 is positioned behind the engine 4. The radiator 50 is located behind the fan. The cooling fan 20 is directly driven by the engine 4. In FIG. 12, the radiator 50 is disposed behind the engine 4, and the cooling fan 20 is mounted behind the radiator 50. In this arrangement, the cooling fan 20 is driven either by a hydraulic motor or by an electric motor 21. Cooling air is sucked from the intake ports 14 in the right and left side covers 12 of the engine compartment 10 as indicated by the arrows. The air then passes through the radiator 50 and is discharged from the exhaust ports 15 of the radiator shutter 13. Another example is disclosed in Japanese Unexamined Utility Model No. 83126/1989.
The structures described above have the following problems. In the examples shown in FIGS. 11 and 12, the flow of the cooling air is indicated by the arrows. That is, the cooling air enters the radiator 50 after passing across the side surfaces of the engine 4. Therefore, the cooling air is prewarmed. Furthermore, the cooling airflow is not smooth because the engine 4 constitutes an obstacle. Hence, the cooling efficiency is not good. For this reason, the radiator 50 needs to have a large surface area. Furthermore, a large amount of airflow is necessary. Additionally, the rotational speed of the cooling fan 20 is high.
In recent years, noises have presented great social problems. Working vehicles have been required to produce reduced levels of noise. One method of reducing the noise level is to lower the rotational speed of the cooling fan 20. For this purpose, it is necessary to improve the cooling efficiency. One method of improving the cooling efficiency is to increase the cooling area of the radiator 50. One conceivable method of increasing the cooling area consists of increasing the height, width, or thickness of the radiator 50. Where the height or width is increased, however, the flow of air across the increased portion is poor. This will impair the efficiency of the cooling fan 20. Where the thickness is increased, the ventilation resistance is increased, and the cooling efficiency drops. Where the height of the radiator 50 is increased, the height H1 of the hood 11 of the engine compartment 10 shown in FIG. 1 increases, deteriorating the backward visibility. If the width is increased, the width of the vehicle is increased.
A wheel loader that is a wheel type working vehicle that usually performs the following operations. First, the loader scoops a hillock. Thereafter, the loader moves backward while the operator is steering the vehicle. Then, the vehicle advances to a location where the soil should be dumped. Therefore, if the backward visibility is deteriorated as mentioned above, it is difficult to drive the vehicle in the backward direction. If the width of the vehicle is increased, the vehicle more easily collides against an obstacle during steering or motion. As a result, the steering performance and the working performance are deteriorated.
In the structure described above, the engine 4, the radiator 50, and the cooling fan 20 are close to each other. The cooling fan 20 is fixed. Therefore, it is difficult to clean the front and rear surfaces of the radiator 50.
In the structure disclosed in the above-cited Japanese Unexamined Utility Model No. 83126/1989, the core of the radiator is split into two parts. One core part is tilted from the other. The cooling area can be increased without increasing the height or width of the vehicle body. However, tanks formed in the core parts are placed in communication with each other and made integral with each other. Consequently, the structure is made complex and expensive. Furthermore, when the radiator is replaced, the whole radiator must be replaced. Hence, it is costly to repair the cooling system.
In view of the foregoing problems, it is an object of the present invention to provide an inexpensive cooling system which is used to cool a working vehicle, secures a large cooling area within a limited space, produces a reduced level of noise, can offer improved backward visibility, and is easy to clean.
The above-described object is achieved by a first embodiment of the present invention that provides a cooling system for use with a wheel type working vehicle having a working implement in the front and an engine in the rear. The cooling system has a plurality of radiators mounted in the rear of the vehicle. The radiators are arranged like the letter xe2x80x9cVxe2x80x9d within a plane.
In the structure described above, the plural radiators are arranged like the letter xe2x80x9cVxe2x80x9d within a plane. Therefore a wider cooling area can be secured within the same width than where a single radiator is used. The rotational speed of the fan can be reduced. Consequently, a lower level of noise can be accomplished. Furthermore, air taken in across the side covers of the engine compartment flows smoothly and can be introduced without passing across the side surfaces of the engine. Hence, the cooling efficiency is improved. Especially in the case of large-sized vehicles, the cost can be reduced by using two small-sized radiators.
A second embodiment of the present invention is based on the first embodiment described above and characterized in that the plural radiators described above are arranged like the letter xe2x80x9cVxe2x80x9d in the rear of the engine. This V-shaped radiator arrangement has a space or an opening in the rear. A single cooling fan is mounted in the opening of the radiator arrangement.
In the structure described above, the radiators are arranged like the letter xe2x80x9cVxe2x80x9d having an opening in the rear and so the radiators are tilted from the side surface of the body. The single cooling fan is mounted in the opening of the V-shaped radiator arrangement. Therefore, air taken in across the side surfaces of the vehicle body flows smoothly. The cooling air passes across the whole surfaces of the radiators while experiencing less resistance. In consequence, the cooling efficiency is improved.
A third embodiment of the present invention is based on the second embodiment described above and characterized in that each of the side surfaces of the radiators described above has an intake port covered by a side cover that can be opened. The top side of the intake port is covered by the hood whose top surface is tilted rearwardly downwardly.
In the structure described above, the radiators are tilted from the side surfaces of the vehicle body. Therefore, the outer surfaces of the radiators can be inspected and cleaned easily by opening the side covers. Furthermore, the rearward visibility is improved, because the top surface of the hood is tilted rearwardly and downwardly. Hence, the vehicle can be driven easily and safely.
A fourth embodiment of the invention is based on the second or third embodiment described above and characterized in that the aforementioned cooling fan is tilted rearwardly and upwardly as viewed from a side.
In this structure, the cooling fan is tilted rearwardly upwardly and so the height at the rear end of the hood can be reduced. Hence, the rearward visibility can be enhanced.
A fifth embodiment of the invention is based on the second, third, or fourth embodiment described above and characterized in that the aforementioned cooling fan is rotatably mounted to a fan support frame. Any one of the left end, right end, top end, and bottom end of the fan support frame is rotatably held to the rear end of the opening of the radiator arrangement.
In the structure described above, any one of the left end, right end, top end, and bottom end of the fan support frame is rotatably held to the rear end of the opening of the radiator arrangement, so that the inner surfaces of the V-shaped arrangement of the radiators can be easily inspected and cleaned by swinging the fan support frame open. Accordingly, the maintainability of the radiators can be improved.
A sixth embodiment of the invention is based on the first or second embodiment described above and characterized in that two radiators form a V-shaped arrangement having an opening in the rear within a plane. The inner ends of the radiators are close to each other. The inner ends of the radiators are tightened to a bracket of L-shaped cross section with bolts such that the bracket fills the gap between the inner ends. A fan shroud that covers the outer periphery of the cooling fan is mounted to the outer ends of the radiators close to the opening. Top and bottom plates are mounted at the top and the bottom, respectively, in a triangular area surrounded by the two radiators and the fan shroud.
In the structure described above, the opening that is formed in the rear of the V-shaped radiator arrangement and located between the two radiators is covered by the bracket at the inner ends of the radiators, the fan shroud around the rear opening, the top plate, and the bottom plate. The cooling air passes across the whole surface of the radiator core without leakage. Therefore, cooling is done efficiently. Since the radiators are tightened to the bracket with the bolts, the radiators can be attached and detached independently. Consequently, only the radiator that needs to be serviced can be replaced. As a result, the repair cost can be curtailed. The replacement operation is facilitated. In consequence, the maintenance cost can be reduced.
Other objects and features of the invention will appear in the course of the description thereof, which follows.